Mental Health Cheat Sheet

The full physiological and behavioural toolkit for your mind: dosed, mechanism-anchored, and rated by how strong the evidence is, including the promising-but-unsettled. Tools to amplify your agency, not a replacement for care you may also need.

The premise, argued throughout, is that you are not a broken machine waiting to be fixed by an expert, but a system whose inputs you can largely control, and that a large, well-evidenced, and badly underused set of physiological and behavioural levers shapes how you feel. The standard model has too often handed people a diagnosis, a prescription, and a waitlist, and called it care. This is the other half: the things you can do, starting today, to change the conditions your mind is running in.

This amplifies rather than replaces. If you are on medication or in therapy and it is helping, this works alongside it (mind the interactions flagged below), and nothing here is a reason to stop a prescribed treatment. The aim is to widen the set of tools in your hands so that fewer people reach the point of crisis, and those who do have more to work with, so as not to leave anyone to rescue themselves from a genuine emergency alone. Second, because mental ill-health drains the very motivation needed to act, the tools are ordered and tagged for leverage and ease: start with the foundations, add the targeted tools, and treat the frontier as optional experiments.

How the evidence tags work, since this cheat sheet deliberately includes the unsettled, as you’d want from a complete map:

• [Foundational]: strong evidence, large effects, low risk; do these first.
• [Solid]: good evidence for a real, useful effect.
• [Promising]: encouraging but incomplete evidence; reasonable to try, hold loosely.
• [Frontier]: early, experimental, or mechanistically plausible but unproven; included because the map should be complete, flagged so you know what you are trying.
• ⚠ Safety: a specific risk or interaction to respect.

I. Read This First

If you are in acute crisis, thinking of ending your life or unable to keep yourself safe, in the grip of psychosis (losing contact with reality), in a sleepless runaway “high” (mania), or have stopped eating or sleeping entirely, that is the point to bring in other hands now: a trusted person, a doctor, or a crisis line. The tools below are what you build the rest of the time and what you return to once stability is back. And one hard line: ⚠ Do not stop a prescribed psychiatric medication abruptly or alone. Discontinuation is a medical process with physiological effects, done gradually and with support.

II. The Foundations

These five do most of the work, and almost everything in the later tiers works better on top of them. If you do nothing else, do these.

Movement [Foundational]

The most reliably antidepressant and anxiolytic thing most people can do, with meta-analytic effects rivalling medication for mild-to-moderate depression, working through neuroplasticity (BDNF), reduced inflammation, dopamine and noradrenaline, and the clearing of kynurenine away from its depressive metabolite.

• Aerobic: ~150 min/week of moderate activity, or 75 of vigorous; even a single brisk walk lifts mood acutely. Zone 2 (conversational pace) builds the base.
• Resistance training: 2-3 sessions/week has its own antidepressant and anti-anxiety evidence, independent of cardio.
• The dose that beats none is “any.” For the depressed, the first rule is to act before motivation returns; start absurdly small (a five-minute walk) and let it compound. See Movement.

Sleep and Circadian Rhythm [Foundational]

Disrupted sleep is both a symptom and a driver of nearly every mental health condition; fixing it is often the highest-yield single move.

• Anchor the clock: consistent wake time (even at weekends), morning daylight within an hour of waking (outdoors beats any indoor light), dim and screen-light-reduced evenings.
• For insomnia specifically, CBT-I is the first-line, gold-standard treatment [Foundational], stronger and more durable than sleeping pills, built on stimulus control (bed for sleep only; if awake 20+ min, get up) and sleep restriction (temporarily compress time in bed to rebuild sleep pressure). App-based versions work.
• ⚠ Treat sleeping pills (Z-drugs, benzodiazepines) as short-term only; they carry tolerance and dependence and do not fix the cause. See Sleep & Circadian Rhythm.

Light [Foundational for seasonal, Solid for non-seasonal]

Light is a direct input to the systems governing mood, sleep, and energy.

• Morning sunlight: 10-30 min of outdoor light early sets the circadian clock and supports serotonin and mood.
• Bright light therapy: a 10,000-lux lightbox for ~20-30 min each morning is well-established for seasonal depression and, on recent meta-analytic evidence, an effective adjunct for non-seasonal depression too. Cheap, fast-acting, low-risk. ⚠ Can trigger mania in bipolar disorder; use with medical guidance there.

Nutrition and the Gut [Foundational]

Diet shifts mood measurably; the SMILES trial showed a Mediterranean-style dietary change produced clinically meaningful improvement in major depression, plausibly via inflammation and the gut-brain axis.

• The pattern that helps: whole foods, high protein from clean meat sources, plenty of plants and fibre, oily fish, olive oil, fermented foods; minimise ultra-processed food, which feeds inflammation and the craving loop.
• Stabilise blood glucose (protein and fibre, fewer refined-carb spikes) to flatten the mood and energy swings that mimic anxiety.
• Feed the microbiome (fibre, fermented foods); the gut-brain axis is a real route to mood. See Nutrition and Gut Health.
• ⚠ If you have any history of disordered eating, apply dietary tools loosely and with support; rigid rules and numbers can do more harm than good here.

Connection and Purpose [Foundational]

Among the heaviest inputs of all, and the easiest to neglect when struggling. Social isolation carries a mortality risk comparable to smoking; loneliness and meaninglessness deepen nearly every condition.

• Connection: regular in-person contact, even small doses; reduce the screen-mediated substitute that displaces it. Recovery needs people, not just protocols.
• Purpose: goal-directed, meaningful activity (work, craft, care, service) is a structural antidepressant. See Connection and Purpose.

III. Targeted Physiological Tools

Breathwork [Solid]

The fastest lever, acting directly on the autonomic nervous system.

• Physiological sigh (double inhale through the nose, long full exhale): the quickest way to down-shift acute stress or anxiety in real time; a few cycles work within a minute.
• Cyclic sighing (extended-exhale breathing) for ~5 min/day: in a controlled Stanford trial it improved mood and lowered anxiety, outperforming an equal dose of mindfulness meditation.
• Slow breathing at ~6 breaths/min (resonance-frequency / HRV breathing) builds parasympathetic tone over time. See Breathing.

Deliberate Cold [Promising]

Cold exposure (cold showers, cold-water immersion) produces a large, sustained rise in dopamine and noradrenaline that can lift mood and build stress tolerance, a form of interoceptive exposure that teaches the system that intense bodily sensation is survivable.

• Dose: brief is enough, 1-3 min cold shower, or short cold-water immersion a few times a week.
• ⚠ Not for people prone to panic (deliberately spiking arousal can backfire); respect cardiac caution and never do cold-water immersion alone in open water. See Thermoregulation.

Deliberate Heat/Sauna [Promising]

Whole-body heating has emerging antidepressant evidence, a single session of whole-body hyperthermia produced a measurable, durable mood lift in a controlled trial, and regular sauna use is associated with better mental health, possibly via heat-shock proteins, inflammation, and endorphins.

• Dose: sauna 15-20 min, a few times a week, as tolerated. ⚠ Hydrate with electrolytes; cardiac and pregnancy caution; not with alcohol.

Sunlight and Time in Nature [Solid for light, Promising for nature]

Beyond circadian light, time in green space (“forest bathing”) has reasonable evidence for lowering stress, cortisol, and rumination. Cheap, pleasant, and easy to combine with movement and connection. See Environment.

Fasting and Time-Restricted Eating [Promising/Frontier]

Time-restricted eating and intermittent fasting may benefit mood and metabolic health via ketones, BDNF, and reduced inflammation, but the mental-health evidence is still thin and individual. ⚠ Not appropriate with any history of disordered eating, in pregnancy, or where it worsens sleep or anxiety. See Fasting.

IV. Nutrients and Supplements

None is a foundation; several have genuine evidence, and the interaction flags matter, especially if you take any psychiatric medication. ⚠ A blanket rule: if you are on an antidepressant or other psychiatric drug, check every supplement below with a doctor or pharmacist before combining; several raise serotonin and can interact dangerously.

Correct deficiencies first [Solid]

Deficiency in any of these can directly cause low mood, anxiety, fatigue, or brain fog; correcting a real deficiency is high-value, supplementing beyond sufficiency usually is not. Worth testing or addressing:

• Vitamin D (common deficiency, linked to depression; supplement if low).
• B12 and folate/methylfolate (deficiency causes mood and cognitive symptoms; relevant to the methylation discussions elsewhere in the section).
• Iron/ferritin (low iron causes fatigue, low mood, and restless legs; especially in menstruating people).
• Magnesium (involved in stress and sleep; glycinate or threonate forms; ~200-400mg; reasonable evidence for anxiety and sleep, low risk).
• Zinc and omega-3 index round these out.

Omega-3 fatty acids [Solid]

EPA-predominant fish oil (~1-2g EPA daily) has meta-analytic support for depression and can augment antidepressants, likely via lowering brain inflammation. ⚠ High doses thin the blood, caution with anticoagulants.

The better-evidenced botanicals [Solid to Promising]

• Saffron (~30mg/day): reasonable trial evidence for depression and anxiety, comparable to low-dose antidepressants in some studies. ⚠ Stay under ~1g/day.
• St John’s Wort (Hypericum): genuinely effective for mild-to-moderate depression, on par with some antidepressants. ⚠ The big one: it is a potent CYP3A4 inducer that weakens many drugs (oral contraceptives, anticoagulants, immunosuppressants, some psychiatric and cancer drugs) and, combined with SSRIs or other serotonergic drugs, can cause serotonin syndrome. Do not combine with other antidepressants, and check it against everything you take.
• L-theanine (~200mg): calms without sedating; useful for acute anxiety and alongside caffeine; low risk.
• Ashwagandha (standardised extract, short-term): promising for stress, anxiety, and cortisol. ⚠ Additive sedation with benzodiazepines, can alter thyroid hormone, possible serotonin interaction with antidepressants, and emerging reports of rare liver injury; short-term use, caution in thyroid conditions.
• Rhodiola: modest evidence for stress-related fatigue; generally well-tolerated.

Targeted compounds [Promising to Frontier]

• Creatine (~5g/day): emerging evidence it may augment antidepressants, possibly more in women, via brain energy metabolism. ⚠ Can worsen mania in bipolar.
• NAC (N-acetylcysteine) (~1200-2400mg/day): promising for OCD, trichotillomania/skin-picking, and as an addiction adjunct, via glutamate and antioxidant pathways. Slow to act (weeks to months).
• Inositol (~12-18g/day): some evidence for panic and OCD; mixed overall.
• Probiotics / “psychobiotics” [Frontier]: specific strains show early promise for mood and anxiety via the gut-brain axis; evidence is preliminary.
• ⚠ Serotonin-precursor caution: 5-HTP, L-tryptophan, and SAMe can each help mood but must not be combined with SSRIs/SNRIs or other serotonergic agents (serotonin syndrome risk). SAMe can also trigger mania in bipolar.
• ⚠ Avoid the genuinely risky frontier: compounds like methylene blue (a potent MAO inhibitor, dangerous serotonin interactions) and “microdose lithium” supplements are sometimes promoted; the risks and interactions are real and the evidence thin. Not without medical oversight.

V. Psychological and Behavioural Tools (Self-Administrable)

These are not pharmacological, but they are physiological in effect, retraining the circuits the conditions run on, and you can largely do them yourself or with a book or app.

• Behavioural activation [Foundational]: for depression, schedule and do small, meaningful or rewarding activities before the desire returns; acting first reopens the reward circuits depression walls off. One of the best-evidenced therapies, and self-directable.
• Graded exposure [Foundational]: for anxiety, panic, and phobia, face the feared thing in steps (a 0-100 ladder), staying with each until the alarm drops, building new safety learning over the old fear. Avoidance feeds anxiety; graded approach dissolves it. See Fear and Hypervigilance.
• Cognitive work/CBT [Foundational]: identify and test the catastrophic or self-attacking thoughts, and rebuild more accurate ones; strengthens the prefrontal brake over the threat and mood circuits. Self-help CBT books and apps have real evidence. Tie to Mental Models.
• Mindfulness meditation [Solid]: regular practice (and structured programmes like MBCT) reduces anxiety and protects against depression relapse; ~10-20 min/day. See Mindfulness.
• Expressive/gratitude writing [Promising]: writing about difficult experiences (Pennebaker-style) and regular gratitude practice both have reasonable evidence for mood and stress, low-cost adjuncts, not headline acts.
• Self-distancing: viewing your situation from the outside (“third-person”) reduces rumination and emotional reactivity.

VI. The Frontier

Included because you asked for the complete map, and because some of this is where the field is genuinely moving, but flagged clearly: these are emerging, often clinical-only, and not established self-care.

• Ketamine/esketamine [Promising, clinical]: rapidly boosts neuroplasticity and can lift treatment-resistant depression within hours; FDA-approved (esketamine) for that use. Administered medically; effects are often short-lived; not a DIY tool.
• Psilocybin and other psychedelics [Frontier, clinical-trial]: striking trial results for depression and addiction, but not approved, and ⚠ MDMA-assisted therapy was rejected by the FDA in 2024 over safety and trial-design concerns. Set and setting and screening matter enormously; self-experimentation carries real psychological risk, especially with any psychosis or bipolar vulnerability.
• Ketogenic/metabolic psychiatry [Frontier]: a ketogenic diet is under serious investigation for bipolar and other serious mental illness via brain energy metabolism; early case series and small trials are encouraging, controlled evidence is still thin. Best pursued, if at all, with clinical support, especially in bipolar.
• Transcranial stimulation [Promising to Frontier]: TMS is an established clinical treatment for treatment-resistant depression (in-clinic, not DIY); tDCS devices are sold to consumers but the evidence is mixed and ⚠ DIY montages carry burn and dosing risks.
• Non-invasive vagus nerve stimulation, HRV biofeedback, floatation-REST [Frontier]: each has early, plausible evidence for anxiety and stress; reasonable low-risk experiments, not proven treatments.

VII. How to Use This

Because the conditions themselves sap motivation, do not try to do everything. The sequence that works:

1. Stabilise the foundations first (Tier 1): sleep, movement, light, food, one human connection. These are 80% of the available return and make everything else work.
2. Add one or two targeted tools (Tier 2) that fit your pattern: breathwork and exposure for anxiety; behavioural activation, light, and morning movement for depression; CBT-I for insomnia; the reset and rewarding-alternatives for addiction.
3. Correct any real deficiencies (Tier 3), and add a well-evidenced supplement or two if useful, respecting the interaction flags.
4. Treat the frontier as optional experiments, one at a time, so you can tell what does what, never as a substitute for the foundations or for help you genuinely need.
5. Start absurdly small. One walk. One physiological sigh. One earlier bedtime. The point is momentum, not perfection. The system changes through repeated small inputs, which is exactly what is doable even on the worst days.

You are the operator of a system with many inputs, most of them in your hands. Use professional help and medication as tools when you need them, hold the few red lines that keep this safe, and otherwise work the levers, patiently and in your own favour.

VIII. Cross-Links

• Mental Health for the section overview
• Why Do I Feel Like This?, Fear and Hypervigilance, Pain and Addiction, and Neurodivergence for the conditions these tools address
• Mental Health Resources for the sources